<!doctype html>
<html lang="en">
 <head>
  <meta charset="UTF-8">
  <meta name="Generator" content="EditPlus®">
  <meta name="Author" content="">
  <meta name="Keywords" content="">
  <meta name="Description" content="">
  <title>Document</title>
 </head>
 <body>
  
 </body>
</html>
<script>
	var a = 4;
	
	switch(a){//break  一旦满足条件运行完后，就会中断当前程序
		case 3:
			alert(3);
			//break;
		case 4:
			alert(4);
			//break;
		case 5:
			alert(5);
			//break;
		case 6:
			alert(6);
			break;
		default:
			alert(7);
			break;
	}
</script>
